Table 3.
Effect of cow feeding system (S: TMR vs. pTMR) and grazing period (P) on milk production and composition.
| Item | TMR | pTMR | Grazing Period # | SEM | p-Values | ||||
|---|---|---|---|---|---|---|---|---|---|
| P1 | P2 | P3 | S | P | |||||
| Raw milk yield (kg/d) | 24.86 | 22.75 | 23.72 a | 22.64 b | 21.52 c | 0.555 | * | ** | |
| Corrected milk yield: | |||||||||
| - FCM—3.5% (kg/d) | 28.81 | 28.14 | 28.64 | 27.67 | 27.49 | 0.622 | n.s. | n.s. | |
| - ECM (kg/d) | 29.23 | 28.36 | 29.21 a | 27.75 ab | 27.33 b | 0.528 | n.s. | * | |
| Milk content (%): | |||||||||
| - fat | 4.48 | 4.96 | 4.78 b | 4.87 b | 5.21 a | 0.202 | ** | * | |
| - protein | 3.91 | 4.04 | 4.15 | 3.90 | 3.91 | 0.094 | n.s. | n.s. | |
| - lactose | 4.72 | 4.58 | 4.44 | 4.53 | 4.65 | 0.045 | * | n.s. | |
| - urea-N | 19.80 | 25.21 | 28.72 a | 25.80 b | 24.62 b | 0.850 | ** | * | |
| - SNF | 9.46 | 9.69 | 9.57 | 9.23 | 9.45 | 0.097 | n.s. | n.s. | |
| Milk yield (kg/d): | |||||||||
| - fat | 1.114 | 1.128 | 1.133 | 1.103 | 1.121 | 0.038 | n.s. | n.s. | |
| - protein | 0.972 | 0.919 | 0.984 a | 0.883 b | 0.841 b | 0.023 | n.s. | * | |
| - lactose | 1.173 | 1.042 | 1.053 | 1.026 | 1.001 | 0.028 | n.s. | n.s. | |
| SCC (×1000 cells/mL) | 143.7 | 245.6 | 285.3 | 254.4 | 195.2 | 21.43 | ** | * | |
TMR: total mixed ration; pTMR: partial mixed ration; SEM: standard error of the mean; SNF: solids non-fat; SCC: somatic cells count; FCM: fat-corrected milk and ECM: energy-corrected milk—calculated according to NRC equations [17]. # Grazing period (3 weeks): P1—May, P2—June, P3—June/July. a–c Mean values within a row without a common superscript differ significantly (p < 0.05). Statistically significant difference: * p < 0.05; ** p < 0.01; n.s.—not significant.